1. Field of the Invention
The present invention relates to raw materials for polyurethane foams and a method for preparing the same. More particularly, the present invention relates to raw materials for anti-cracking polyurethane foams and a method for preparing the same.
2. Description of the Background Art
In general, polyurethane foams is obtained by reacting a polyol component and a isocyanate component in the presence of a foam blowing agent, a reaction catalyst and other additives.
The polyurethane foams have the most excellent adiabatic material among organic and inorganic adiabatic materials. With the merits of excellent adiabatic property due to the construction of independent pores and that a low density foams can be prepared by controlling a use amount and a type of a foam blowing agent, the polyurethane foams is generally adopted to a refrigerator, a freezing container or a low-temperature warehouse that need a high adiabatic property.
In case that rigid polyurethane foams are used for a refrigerator, it also serves to maintain an intensity of a refrigerator as well, besides the role as the adiabatic material.
In addition, a structure and configuration of the refrigerator affects a polyurethane flow, and the basic materials of a refrigerator are constructed by triple conjugate of iron/polyurethane foams/liner, so that a stress caused due to a difference of linear expansion coefficients of the materials is additionally applied to the refrigerator. Such a structure varies under many testing conditions in a refrigerator state according to mechanical characteristics of the polyurethane foams at a middle portion. Especially, failing to tolerate the stress, a foam crack occurs therein to even cause a crack in the liner being in contact therewith.